roof condensation

hi there hope someone can help,i recently noticed water dripping through my bathroom ceiling and down the walls,also some in the adjacent bedroom upstairs ,i went into my loft to have a look and noticed there were drips all over the place .my loft has been insulated with poly foam and in varoius places water was dripping through the foam i have been in the house for 2 years ,last winter id noticed a similar problem with less severe leakage ,the foam is in between the rafters i only seem to get the problem in winter which leads me to think it is a condensation problem ive been in the loft to check when its raining and there are no leaks at all .ive spoken to a few roofers and they are very skeptical about the product saying it can make the roof sweat,yet its advertised everywhere as a good product proviving good insulation ,does anybody out there have any info about this ,ive looked for information regarding whether it is a cause of condensation but have found nothing to say it is ,hope u can help thanks

ventilate the loft better to get a good throughflow of air from one side to the other. Pull back any insulation that blocks the eaves. Look for any gaps in the ceiling allowing warm damp air to rise into the loft, e.g. round downlighters or pipes. Check that loft water tanks have lids and are not warm.

reduce moisture inside the house. Common causes are draping wet washing on the radiators, and failing to use an extractor in the bathroom.

BTW foam spraying has a poor reputation on here. Don't believe the advertising.

see also "similar topics" at the foot of this page.

also //search.diynot.com/forum_search.php?q=loft+condensation&limit=10&stype=0&sort=post_time

thanks for your reply i dont have extractor in the bathroom although there is an airbrick vent next to shower ive had a roofer to look at the roof he said it looks ok except he also isnt a fan of foam insulation .im probably leaning towards getting a new roof ,the house is over 40 years old so maybe now is the time .getting rid of the foam and installing some modern type felt maybe would be better

if you have a shower and no extractor, you will be making a lot of steam in the bathroom. A good fan (preferably a Centrifugal one) will suck it out and create enough suction to prevent the steam drifting into the house and loft. One could be fitted in the airbrick vent, or you could hire a core drill to make a 105mm hole through the wall for the duct.

Pul the loft insulation out of the eaves to improve loft ventilation.